KR20010009955A - Method of Driving Plasma Display Panel - Google Patents

Abstract

PURPOSE: A drive method of plasma display panel is provided to compensate the low and high levels of a scale to embody a linear scale and enhance contrast by controlling a sustain pulse weight value of a sub field related to plural groups of brightness and brightness by the linear scale CONSTITUTION: The plasma display panel comprises a data driver(16), a scan/sustain driver(18), a sustain driver(20), a timing controller(14), an A/D converter(2), a frame memory(4), a data sensor(6), a comparison/operation controller(10), a mode selector(12) and a reference data setting part(8). The data driver(16) drives data electrodes of the PDP(22). The scan/sustain driver(18) drives scan/sustain electrodes of the PDP. The sustain driver(20) drives sustain electrodes of the PDP. The timing controller(14) is commonly connected to the drivers(16,18,20). The A/D converter(2) converts an input video signal into a digital video data. The frame memory(4) is connected between the converter and the data driver(16). The data sensor(6), controller(10) and mode selector(12) are serially connected between the memory(4) and the controller(14).

Description

Method of driving plasma display panel {Method of Driving Plasma Display Panel}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of driving a plasma display panel, and more particularly, to a method of driving a plasma display panel capable of linear gradation by compensating low and high levels.

Recently, a plasma display panel (hereinafter referred to as "PDP") has attracted attention as a thin and lightweight display device. In the case of displaying a video signal (for example, a television signal) with this PDP, a modulation method is generally used in which the number of emission is proportional to the video signal. Specifically, the video signal is digitized and each frame period is divided into subfield periods corresponding to the number of bits of the digitized video data. In each subfield period, gradation display is performed by emitting light a number of times proportional to the weight of digital video data.

For example, when an image is displayed in 256 gray scales using 8-bit video data, one frame display period (for example, 1/60 second = about 16.7 msec) in each pixel is divided into eight sub-frames as shown in FIG. It is divided into field periods SF1 to SF8. Each subfield period SF1 to SF8 is further divided into a reset period RP, an address period AP and a display period SP, and the display period SP is 1: 2: 4: 8:... The weight is given at the ratio of 128. The reset period RP and the address period AP are equally assigned to each subfield period (for example, the periods of the RP and the AP are 1.5 ms). In this PDP driving method, the display order of subfield periods corresponding to each bit is in a constant order as in the example of SF1, SF2, SF3, SF4, SF5, SF6, SF7, SF8. Here, in the address periods of the respective subfields SF1 to SF8, one bit data of 8-bit video data corresponding to each discharge cell is sequentially applied in line to generate selective address discharge. Specifically, data of the least significant bit in the address period of the first subfield SF1, data of the next lower bit in the address period of the first subfield SF2, and in the address period of the eighth subfield SF8. 촤 Upper bits of data are applied. In the sustain period of each of the subfields SF1 to SF8, the discharge is maintained only in the discharge cells in which the address discharge has occurred. In this case, 1: 2: 4: 8:... In the sustain period SP of each subfield SF1 to SF8. The weight is given at the ratio of: 128 and gradation display corresponding to the weight is performed. Then, one gray level among 256 levels is implemented by combining the gray levels displayed in each subfield of one frame period.

However, in the gray scale expression method using the subfield method as described above, since the low level and the high level of the gray level are not properly expressed, the sustain pulses supplied from the portions A and B in which the low level and the high level are represented as shown in FIG. It has nonlinearity that is not proportional to the number. Specifically, in the low level display section A, since the basic background brightness exists due to repeated reset and address discharge for each subfield, the display is displayed at a level higher than the level to be expressed. Further, in the high level display section B, white saturation occurs and is displayed at a level lower than the level to be expressed. Specifically, when discharge is continuously generated for a predetermined time or more over a plurality of subfields for high level expression, the number of sustain pulses supplied with brightness due to the reduction of ions due to the combination of ions in the discharge space and the collision with partition walls, etc. White saturation occurs, which is not proportional. As described above, in the conventional PDP driving method, since the desired gray level is not expressed at the low level and the high level, there is a problem that the contrast is lowered and the image is not clearly expressed.

Accordingly, an object of the present invention is to provide a PDP driving method capable of implementing linear gradation by compensating for low and high levels of gradation.

Another object of the present invention is to provide a PDP driving method which can improve the contrast and improve the brightness by implementing linear gradation.

1 is a diagram showing a subfield driving procedure in one frame period.

2 is a graph showing the relationship between the number of sustain pulses and the brightness in a conventional PDP.

3 is a diagram illustrating an example of data value grouping applied to a PDP driving method according to an exemplary embodiment of the present invention.

4 is a view showing a PDP driving apparatus applied to the present invention.

<Brief description of symbols for the main parts of the drawings>

2: A / D converter 4: Frame memory

6: Data sensing unit 8: Reference data setting unit

10: comparison / operation control unit 12: mode selection unit

14: timing controller 16: data driver

18: scanning / holding drive unit 20: holding drive unit

22: PDP

In order to achieve the above objects, the PDP driving method according to the present invention is characterized by grouping the data value to be displayed and adjusting the sustain pulse weight of the subfield related to the data value for each group.

Other objects and advantages of the present invention in addition to the above object will be apparent from the description of the preferred embodiment of the present invention with reference to the accompanying drawings.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to FIGS. 3 to 5.

In the PDP driving control method according to the present invention, a data value, that is, a luminance value, is detected for each frame or subfield, divided into a plurality of groups, and then the number of sustain pulses supplied depending on the data value is adjusted accordingly. do. For example, when 256 gray levels are represented, luminance values are divided into four groups as illustrated in FIG. 3. Specifically, the first group G1 including the luminance values of 1 to 15, the second group G2 including the luminance values of 16 to 63, and the third group G3 including the luminance values of 64 to 191. , A fourth group G4 containing luminance values of 192 to 255 is divided. According to the first to fourth groups G1 to G4, the weight of the number of sustain pulses related to the corresponding subfield is adjusted and supplied as shown in Table 1 below.

Group type (luminance value) Maintenance pulse weight G1 (1-15) 2 ⁿ -2 G2 (16-63) 2 ⁿ -1 G3 (64-191) 2 ⁿ G4 (192-255) 2 ⁿ +1

In the above Table 1, when the luminance value belongs to the first group G1, it is usually a low level, and the number of sustain pulses is supplied less than before, so that the luminance value is higher than the desired luminance level as in the prior art. Will be. For example, a sustain pulse having a weight of 2 ⁿ -2 is supplied to subfields related to displaying the luminance value of the first group G1. When the luminance value belongs to the second group G2, a sustain pulse having a weight of 2 ⁿ −1 is supplied to related subfields. Since the luminance value of the third group G3 is a period in which the luminance value is linearly proportional to the number of sustain pulses, the sustain pulses having a weight of 2 ⁿ are supplied to related subfields. In the case where the luminance value belongs to the fourth group G4, it corresponds to a high level, and the number of sustain pulses is increased so as to prevent the display from being lower than the desired luminance level due to white saturation. . In this case, a sustain pulse having a weight of 2 ⁿ +1 is supplied to the subfields related to displaying the luminance value of the fourth group G4.

For example, when a luminance value of an arbitrary discharge cell is 37, this corresponds to the second group G2 and 2 ⁿ − in each of the first, third, and sixth subfields SF1, SF3, SF6 associated with it. A sustain pulse having a weight of 1 is supplied. In other words, it is possible to compensate the conventional nonlinearity by supplying a sustain pulse having a weight of SF1: SF3: SF6 = 0: 3: 34. In addition, when the luminance value is 127, the first, second, third, fourth, fifth, sixth, and seventh subfields SF1 to SF7 that are related to the third group G3 and are related thereto are conventional. As shown in FIG. 2, a sustain pulse having a weight of 2 ⁿ is normally supplied. In the case where the luminance value is 200, a sustain pulse having a weight of 2 ⁿ +1 in each of the fourth, seventh, and eighth subfields SF4, SF7, and SF8, which corresponds to the fourth group G4, is associated with the fourth group G4. Will be supplied. In other words, by supplying a sustain pulse having a weight of SF4: SF7: SF8 = 9: 65: 129, it is possible to compensate for the conventional nonlinearity.

Such a method of controlling the number of sustain pulses can be applied to the subframe driving method and the subfield driving method (that is, the ADS driving method), which are ordinary gray scale implementation methods. In this case, a method of controlling the number of sustain pulses by sensing data values in line units may be easily applied to the subframe driving method. On the other hand, in the subfield driving method, since the data value of each pixel or some line is different from each other, it is impossible to apply the unit of line, and instead, the method of controlling the number of sustain pulses by sensing the average value of the data value in the unit of subfield or frame. Can be applied. In other words, it is determined which group among the four groups the data average value calculated in the subfield or frame unit is supplied with a sustain pulse having a weight corresponding to the group.

In addition, by sensing the data in units of frames, the amount of on / off is compared, and the weight of the sustain pulse is adjusted according to which group it belongs to by detecting the amount of data regardless of the field or frame. In this case, it is possible to control up to the minute portion of the brightness level with respect to the gradation level and the tilt can be controlled, so that the desired gradient can be obtained by increasing or decreasing the gradation portion of the specific portion. In particular, even when the characteristics are different from panel to panel, the same image quality may be obtained by unifying the characteristics when the weight control method of the above-described sustain pulse is applied. Normally, the slope is a value obtained by dividing the gradation level by the number of sustain pulses. If the slope is constant, a linear slope can be obtained. It is also possible to adjust the fine inclination constantly or nonlinearly.

4, there is shown a PDP driving apparatus applied to the present invention. 4 includes a data driver 16 for driving data electrodes of the PDP 22, a scan / hold driver 18 for driving scan / hold electrodes of the PDP 22, and a PDP 22; A sustain driver 20 for driving sustain electrodes of the &lt; RTI ID = 0.0 &gt;), a timing controller 14 commonly connected to the data driver 16, the scan / hold driver 18 and the sustain driver 20, &lt; / RTI &gt; Analog-Digital (hereinafter referred to as AD) converter 2 for converting into image data, frame memory 4 connected between AD converter 4 and data driver 16, and frame memory ( 4) and the data sensing unit 6 connected in series between the timing control unit 14, the comparison / operation control unit 10 and the mode selection unit 12, and the reference data setting unit connected to the comparison / operation control unit 10. Let (8) be a structure.

In FIG. 4, the A-D converter 2 converts an input analog video signal into digital video data and outputs the digital video data. The frame memory 4 stores and outputs image data from the A-D converter 2 in units of frames. The data detection unit 6 detects and outputs the data value from the frame memory 4 in a predetermined unit (for example, a line, a subfield or a frame). The reference data setting unit 8 sets the upper limit value of the first to third groups as a reference value by dividing the predetermined group into four groups according to the luminance value, for example, as shown in Table 1 above. In other words, the reference data setting unit 8 sets the upper limit values 15, 63, 191 of the first to third groups as the first to third reference values, respectively. The comparison / operation control unit 10 compares the data value detected by the data detection unit 6 with the first to third reference values set by the reference data setting unit 8 to determine which group mode the detected data value corresponds to. The output will be judged. Specifically, when the detected data value is smaller than or equal to the first reference value, the detected data value is determined and output in the first group mode. When the detected data value is larger than the first reference value and smaller than or equal to the second reference value, the second group mode is larger than the second reference value. When the value is less than or equal to the third reference value, the output is determined as the third group mode, and when the value is greater than the third reference value, the output is determined as the fourth group mode. In response to the group mode output from the comparison / operation control unit 10, the mode selector 12 adjusts the number of sustain pulses of the subfields related to the group according to the weight as shown in Table 1 above. Will be controlled. The timing controller 14 controls the drive timing of the data driver 16, the scan / sustain driver 18, and the sustain driver 20 in response to the input horizontal and vertical synchronization signals H and V. FIG. In particular, the timing controller 14 controls the timing of the scan / sustain driver 18 and the sustain driver 20 in the subfield concerned under the control of the mode selector 12. The data driver 16 inputs data from the frame memory 4 under the control of the timing controller 14 and supplies the data to the data electrodes of the PDP 22. The scan / sustain driver 18 supplies the scan pulse and the sustain pulse to the scan / hold electrodes of the PDP 22 under the control of the timing controller 14. The sustain driver 20 supplies a sustain pulse to the sustain electrodes of the PDP 22 under the control of the timing controller 14.

As described above, the PDP driving apparatus of the present invention divides the data value, that is, the luminance value into a plurality of groups, detects the data value in units of lines, subfields, or frames, and adjusts the sustain pulse weight of the relevant subfield for each corresponding group. Linear gradation can be realized by compensating for low and high levels of gradation.

As described above, according to the PDP driving method according to the present invention, after dividing the data value, that is, the luminance value into a plurality of groups, the data value is detected in units of lines, subfields, or frames, and the sustaining pulse of the relevant subfields for each corresponding group is detected. By adjusting the weight, linear gradation can be realized by compensating for low and high levels of gradation. As a result, the contrast of the PDP can be improved and the brightness can be increased.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

Claims (5)

Grouping a data value to be displayed and adjusting a sustain pulse weight of a subfield related to the data value for each group. The method of claim 1, And detecting the data value in any one of a subfield and a frame. The method of claim 1, And grouping the data value according to the level of the data value. The method of claim 3, wherein The data values A group containing data values in which gray scales are linearly represented, At least one group non-linearly represented and containing low-level data values, A method of driving a plasma display panel, characterized in that the grouping is performed in at least one or more groups including grayscales and non-linear data values. The method of claim 3, wherein Reduce a sustain pulse weight of a subfield associated with groups including the low level data value, And increasing the sustain pulse weight of the subfield associated with the groups including the high level data value.